Digitizer systems are used as computer input devices for capturing data, handwritten signatures, text, drawings, symbols and the like. Digitizing tablets and touch-screens are exemplary digitizer systems used to replace a mouse as a primary pointing and navigation device for desktop computers. A user interacts with the digitizer system by positioning and moving an object such as stylus and/or a finger over a sensing surface of the system, e.g. a tablet and/or a touch screen. Position of the object with respect to the sensing surface is tracked by the digitizer system and interpreted as a user command.